Дифференциальный фон электрического сигнала, снимаемого с индукционной магнитной головки

Abstract

Experimental dependences U(t) of the electric voltage taken from an induction magnetic head (MH) moving relative to a magnetic carrier (MH) are presented. The backgrounds of the edges of the MN, local defects of the MN, the background of the inhomogeneous magnetic field of the local source, the backgrounds of defects and structural inhomogeneities of the object, the etheric electromagnetic background, the background of the quality of the surface of the object and surface microscopic inhomogeneities of the material have been identified and investigated. The resonant backgrounds of self-excitation of the measuring system on the signals of the edges of the MN, defects of the MN, instrument and network pickups and interference, object defects, and etheric electromagnetic fields are revealed and investigated. Resonance peaks are the result of self-excitation of the measuring system, which includes the MG, and arise on the trailing edges of any signals of sufficient magnitude, the duration of the trailing edge of which is about a quarter of the period of natural oscillations of the measuring system. The amplitude and frequency spectra of the background signals of object defects, MI and noise and the analytical expressions describing them are determined. The results of the extraction of the useful signal from the complete signal recorded on the MN are shown. Investigations of the differential background of an electric signal allow, together with the previously developed methods of hysteresis interference, to control the properties of objects in an automatic mode with program control, which significantly increases the sensitivity and accuracy of control. To achieve this goal, it is recommended to set the parameters of the measurement system at the threshold of the onset of natural free oscillations in it.